This invention relates to a method and an apparatus for soaking steel, in which cold steel pieces stored outside the arrangement are subjected to a prehating treatment and subsequently to a soaking treatment with or without hot steel peces delivered from an ingot-making position.
Hitherto, the steel making furnace such as a converter, an open-hearth furnace, an electric furnace or the like has been operated in a batch-wise manner, so that different sorts of steel pieces have been discontinuosuly produced in the cogging factory. On the contrary, since the rolling mill is operated continuously, the soaked steel pieces must be always supplied continuously to the rolling mill. Thus, some of the excess steel pieces must be temporarily stored outside the arrangement, and an appropriate control of cooling and reheating of such the excess steel pieces is extremely difficult, which seriously affects to quality and yield of the products in the subsequent rolling mill as well as the manufacturing capacity in the continuous operation. Furthermore, so-called the walking-beam furnace is known as a furnace useful for the soaking treatment, which is designed to reheat the cold steel pieces passed through the cooling treatment. The furnace of this type has the disadvantages that its heating capacity must be large that the furnace inevitably includes movable components at high operational costs and thus is not tolerable with a labor-saving purpose.